PS-8 Validating the use of dataloggers to measure standing behavior of yearling Angus Bulls on hilly terrain

The goal of this study was to evaluate the reliability of the HOBO Pendant G Accelerometer Datalogger (Onset Computer Corporation, Bourne, Massachusetts, USA) in measuring standing and lying behavior of yearling bulls in a pen with both flat and sloped terrain. The study was conducted with 6 focal bulls selected from a pen of 26 Angus bulls. Data were collected during two separate 2-week sessions (4 weeks total). During this period, the accelerometers recorded leg orientation in the y-axis at 1-minute intervals to determine time spent standing and lying. To validate the accelerometer data, 35 in-person observational sessions were conducted. Each live observation focused on one individual bull. Trained observers noted whether the bull was standing or lying as well as the bull’s location in the pen (on hill or flat terrain) using 1-minute scan sample intervals for 3 hours. Data analysis was conducted using RStudio (R version 3.6.0). Spearman correlation tests were performed to compare the observed standing behavior to the accelerometer data. The correlations were calculated for the entire dataset as well as for individual terrain types (flat and hill). The correlation coefficient (r) between observed standing time and accelerometer standing time was 0.92 for all observations, indicating a strong positive relationship. For the analysis of standing behavior on the hill, the correlation increased to r = 0.95, and on the flat terrain, it remained similarly high at r = 0.92. These results demonstrate that the Hobo Pendant G Acceleration Dataloggers are reliable for tracking standing and lying behavior in a pen with varying terrain types.